Claim CH430:

Baumgardner's computer model shows that runaway subduction explains how
the global flood occurred. The cold, heavy crust of the ocean floor sinks
into the lighter, hotter mantle, releasing gravitational potential energy
as heat. Runaway subduction posits that this process greatly accelerated:
"As the plates deform the surrounding rock, the mechanical energy of
deformation is converted into heat, creating a superheated 'envelope' of
silicate around the sinking ocean floor. Silicate is very sensitive to
heat, so it becomes weaker, allowing the plates to sink faster and heating
the envelope still further, and so on, faster and faster. As the plates
pull apart, the gap between them grows into a broadening seam in the
planet. This sends a gigantic bubble of mantle shooting up through these
ridges; [w]hich displaces the oceans; [w]hich creates a huge flood" (Burr
1997, 57). God "caused an enormous blob of hot mantle material to come
rushing up at incredible velocity through the underwater midocean ridges.
The material ballooned, displacing a tidal wave of sea water over the
continents. . . . Then, after 150 days (Genesis 7:24), the bubble
retreated with equal speed into the Earth" (Burr 1997, 56).

Source:

Burr, Chandler, 1997. The geophysics of God. US News and World Report
122 (June 16): 55-58.

Response:

Baumgarder's theory still does not work without miracles, as
Baumgardner himself admitted (Baumgardner 1990a, 1990b). The thermal
diffusivity of the earth would have to increase ten thousandfold to get
the subduction rates proposed, and something would have to cause the
advance and retreat of the magma bubble (Matsumura 1997). Miracles
would also have been necessary to cool the new ocean floor and to raise
sedimentary mountains in months rather than in the millions of years it
would ordinarily take.

The miraculously lowered viscosity would likely also lower frictional
heating, removing the heat source that the model needs to accelerate
the subduction (Matsumura 1997).

A series of events such as the magma bubble Baumgardner described would
create "an enormous volcanic province in a single region. So, where is
it?" (Geissman, quoted in Matsumura 1997, 30). The incredible amount
of subduction proposed would also have produced much more vulcanism
around plate boundaries than we see (Matsumura 1997).

Baumgardner estimated a release of 1028 joules from the subduction
process. This is more than enough to boil off all the oceans. In
addition, Baumgardner postulated that the mantle was much hotter before
the Flood (giving it less viscosity); that heat would have to go
somewhere, too.

Baumgardner's own modeling shows that during the Flood, currents would
be faster over continents than over ocean basins (Baumgardner and
Barnette 1994), so sediments should, on the whole, be removed from
continents and deposited in ocean basins. Yet sediments on the ocean
basin average 0.6 km thick, while on continents (including continental
shelves), they average 2.6 km thick (Poldervaart 1955).

Cenozoic sediments are post-Flood according to this model. Yet
fossils from Cenozoic sediments alone show a sixty-five-million-year
record of evolution, including a great deal of the diversification of
mammals and angiosperms (Carroll 1997, chaps. 5-6, 13).

Terra, the computer program that Baumgardner created, is a useful
computer program for modeling convection, but the program adds no
credibility. Unreal assumptions of runaway subduction will produce
unreal conclusions.

References:

Baumgardner, John R., 1990b. The imperative of non-stationary natural
law in relation to Noah's Flood. Creation Research Society
Quarterly
27(3): 98-100.

Baumgardner, John R. and D. W. Barnette, 1994. Patterns of ocean
circulation over the continents during Noah's Flood. Proceedings of
the third international conference on creationism. Pittsburgh, PA:
Creation Science Fellowship, pp. 77-86.

Carroll, Robert L., 1997. Patterns and Processes of Vertebrate
Evolution, Cambridge University Press.